#!/usr/bin/env python3

# -*- coding: utf-8 -*-

from __future__ import absolute_import, division, unicode_literals

# Copyright (C) 2018 Ben McGinnes <ben@gnupg.org>

#

# This program is free software; you can redistribute it and/or modify it under

# the terms of the GNU General Public License as published by the Free Software

# Foundation; either version 2 of the License, or (at your option) any later

# version.

#

# This program is free software; you can redistribute it and/or modify it under

# the terms of the GNU Lesser General Public License as published by the Free

# Software Foundation; either version 2.1 of the License, or (at your option)

# any later version.

#

# This program is distributed in the hope that it will be useful, but WITHOUT

# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

# FOR A PARTICULAR PURPOSE.  See the GNU General Public License and the GNU

# Lesser General Public License for more details.

#

# You should have received a copy of the GNU General Public License and the GNU

# Lesser General Public along with this program; if not, see

# <https://www.gnu.org/licenses/>.

import gpg

import os.path

print("""

This script generates a new key which does not expire.

The gpg-agent and pinentry are invoked to set the passphrase.

""")

c = gpg.Context()

homedir = input("Enter the GPG configuration directory path (optional): ")

uid_name = input("Enter the name of the user ID: ")

uid_email = input("Enter the email address of the user ID: ")

uid_cmnt = input("Enter a comment to include (optional): ")

key_algo = input("Enter the key algorithm, RSA or DSA (default is RSA): ")

key_size = input("Enter the key size (2048-4096, default is 2048): ")

if homedir.startswith("~"):

    if os.path.exists(os.path.expanduser(homedir)) is True:

        c.home_dir = os.path.expanduser(homedir)

    else:

        pass

elif os.path.exists(homedir) is True:

    c.home_dir = homedir

else:

    pass

if uid_cmnt:

    userid = "{0} ({1}) <{2}>".format(uid_name, uid_cmnt, uid_email)

else:

    userid = "{0} <{2}>".format(uid_name, uid_email)

if key_algo.lower() == "dsa":

    ka = "dsa"

else:

    ka = "rsa"

if len(key_size) == 4:

    try:

        ks0 = int(key_size)

    except ValueError:

        ks0 = None

    if ks0 is None:

        ks = "2048"

    else:

        if ks0 < 2048:

            ks = "2048"

        elif ka == "dsa" and ks0 > 3072:

            ks = "3072"

        elif ka == "rsa" and ks0 > 4096:

            ks = "4096"

        else:

            ks = key_size

else:

    ks = "2048"

keyalgo = "{0}{1}".format(ka, ks)

newkey = c.create_key(userid, algorithm=keyalgo, expires=False,

                      passphrase=True, certify=True)

key = c.get_key(newkey.fpr, secret=True)

if ka == "rsa":

    newsub = c.create_subkey(key, algorithm=keyalgo, expires=False,

                             passphrase=True, encrypt=True)

else:

    newsub = c.create_subkey(key, expires=False, passphrase=True,

                             encrypt=True)